The biggest pop star in America today is a man named Karl Martin Sandberg. The lead singer of an obscure ’80s glam-metal band, Sandberg grew up in a remote suburb of Stockholm and is now 44. Sandberg is the George Lucas, the LeBron James, the Serena Williams of American pop. He is responsible for more hits than Phil Spector, Michael Jackson, or the Beatles.

After Sandberg come the bald Norwegians, Mikkel Eriksen and Tor Hermansen, 43 and 44; Lukasz Gottwald, 42, a Sandberg protégé and collaborator who spent a decade languishing in Saturday Night Live’s house band; and another Sandberg collaborator named Esther Dean, 33, a former nurse’s aide from Oklahoma who was discovered in the audience of a Gap Band concert, singing along to “Oops Upside Your Head.” They use pseudonyms professionally, but most Americans wouldn’t recognize those, either: Max Martin, Stargate, Dr. Luke, and Ester Dean.

Most Americans will recognize their songs, however. As I write this, at the height of summer, the No. 1 position on the Billboard pop chart is occupied by a Max Martin creation, “Bad Blood” (performed by Taylor Swift featuring Kendrick Lamar). No. 3, “Hey Mama” (David Guetta featuring Nicki Minaj), is an Ester Dean production; No. 5, “Worth It” (Fifth Harmony featuring Kid Ink), was written by Stargate; No. 7, “Can’t Feel My Face” (The Weeknd), is Martin again; No. 16, “The Night Is Still Young” (Minaj), is Dr. Luke and Ester Dean. And so on. If you flip on the radio, odds are that you will hear one of their songs. If you are reading this in an airport, a mall, a doctor’s office, or a hotel lobby, you are likely listening to one of their songs right now. This is not an aberration. The same would have been true at any time in the past decade. Before writing most of Taylor Swift’s newest album, Max Martin wrote No. 1 hits for Britney Spears, ’NSync, Pink, Kelly Clarkson, Maroon 5, and Katy Perry.

Millions of Swifties and KatyCats—as well as Beliebers, Barbz, and Selenators, and the Rihanna Navy—would be stunned by the revelation that a handful of people, a crazily high percentage of them middle-aged Scandinavian men, write most of America’s pop hits. It is an open yet closely guarded secret, protected jealously by the labels and the performers themselves, whose identities are as carefully constructed as their songs and dances. The illusion of creative control is maintained by the fig leaf of a songwriting credit. The performer’s name will often appear in the list of songwriters, even if his or her contribution is negligible. (There’s a saying for this in the music industry: “Change a word, get a third.”) But almost no pop celebrities write their own hits. Too much is on the line for that, and being a global celebrity is a full-time job. It would be like Will Smith writing the next Independence Day.